Evaluation of the seismic behavior factor of reinforced concrete frame structures based on comparative analysis between non-linear static pushover and incremental dynamic analyses

Abstract

The seismic behavior factor R (noted q in the european seismic design code, the Eurocode 8) of reinforced concrete frame structures is evaluated based on comparative analysis between non-linear static pushover and non-linear incremental dynamic analyses. For this purpose, three-, six-, and nine-storey reinforced concrete frame structures, considered as low-, medium-, and high-rise frame, respectively, were designed according to reinforced concrete code BAEL 91 and Algerian seismic code RPA 99/Version 2003. Non-linear static pushover analysis using inverted triangular loading pattern and incremental dynamic analysis using a set of seven time-history earthquake records were carried out to compute the R factor components, such as ductility and overstrength factors, with the consideration of failure criteria at both member and structural levels. The results obtained by non-linear static pushover and incremental dynamic analyses are compared. According to the analysis results, it is observed that in the case of non-linear static pushover analysis, the value of the seismic behavior factor decreases as the number of stories increases, whereas in the case of non-linear incremental dynamic analysis, the trend observed is not the same: the value of the seismic behavior factor increases as the number of stories increases. This result shows that the value of the seismic behavior factor depends, among others parameters, on the height of a structure, which parameter is not taken into account by the seismic design codes. In the light of the information obtained from incremental dynamic analyses, it is observed that the value of the seismic behavior factor adopted by the seismic design code RPA 99/Version 2003 is overestimated, especially for low-rise frame structure. This paper also provides conclusions and the limitations of this study.